This application aims at fostering further integration of those research groups at SKI which use the tools and techniques of Molecular Biology. Those groups probe many aspects of the long range search for basic information which is needed for the unravelling of the mystery of neoplastic growth. The approaches include characterization and purification of informal macromolecules, the modes through which agents from nucleic acids to hormones express themselves, and the controls which regulate the expressions. A dozen investigations deal with fundamental aspects of model viruses, their structure, transport, replication, interactions and expressions of their characters. Mammalian cell hybrids are utilized to study transfer of genetic information and of regulation of gene expressions at the chromosomal level. Two projects center on oncogenic derivatives from purines and on transplacental oncogenesis. Several others probe for primary effects of chemical oncogens on the control of key metabolic processes. Cell differentiation studies deal with thymocytes, lymphocytes and the macromolecular controls of normal and leukemic hematopoiesis. Numerous collaborations are noted and the potential for others is implicit. There is no doubt - in the biologist's mind - that the questions being asked are the types which must be answered before there can be an understanding of, and rational approach to, the control of cancer.